1. Field of the Invention
The disclosure generally relates to a communication device and an antenna structure therein, and more particularly, relates to a communication device and an antenna structure for combining an open-slot antenna and a monopole antenna that are excited to form a low frequency band and a high frequency band, respectively. By disposing a notch of the open-slot antenna toward a short edge of a ground element of the communication device, the communication device and the antenna structure therein can reduce influence of a hand of a user on antenna performance.
2. Description of the Related Art
With progress in the mobile communication industry, mobile communication devices have become smaller and thinner; therefore, antennas applied in the mobile communication devices are integrated with nearby elements and be operated to cover wider frequency bands. With respect to traditional antenna designs, an antenna element requires a clearance space on a system circuit board, and the clearance space cannot be utilized again by other elements. This limits the use of the space on the system circuit board, and it is difficult to minimize the antenna element. Further, when a mobile communication device is used, disposition of the antennas determines how the mobile communication device is influenced by a hand of a user. For example, U.S. Pat. No. 7,768,466 B2, “Multiband folded loop antenna”, discloses an antenna of a mobile phone that occupies a three-dimensional space. The antenna of the mobile phone is disposed on an edge of a ground plane, and occupies the whole edge of the ground plane so as to cover wider frequency bands. The antenna of the mobile phone cannot be closely integrated with the surrounding ground plane; therefore, the inner space of the mobile phone is wasted. In addition, since the clearance space on which the antenna of the mobile phone is disposed cannot be incorporated with other radiating elements excited to form other resonant modes, the antenna of the mobile phone cannot cover more operating bands. While a user is using a mobile communication device including the antenna, radiation performance of the antenna tends to be influenced by different hand positions of a user.